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By John Parianos

"Seafloor mining provides significant potential economic benefits for many Pacific nations that may be "land poor" but "coastline rich," meaning they have the potential to utilize and profit from the mineral wealth within their Exclusive Economic Zones that extend 200 nautical miles (360 km) out from their coastlines. The Independent State of Papua New Guinea (the State) recognizes this tremendous opportunity and is taking a leadership role in this emerging industry by becoming a 15% partner in Solwara 1 (with an option to increase their investment to 30%).The Solwara 1 Project has been gaining momentum since Nautilus Minerals and the State signed an Agreement on April 24. This new agreement with the State in which they have staked a minimum 15% interest as a meaningful partner, underscores the State’s continued and widespread support for the Project. Signing of this Agreement was a historical occasion and a milestone achievement for Nautilus Minerals and the people of PNG.The machinery being built for the Solwara 1 Project is taking shape. The Seafloor Production Tools are now over 90 percent complete. Assembly of the biggest tool, the Bulk Cutter, was completed in April this year and assembly work on the Collecting Machine and the Auxiliary Cutter commenced in May and June this year respectively. The Riser and Lifting system, which will be used to transfer the mined material from the seafloor to the surface within an enclosed system, is over 50 percent complete. The critical path for the Solwara Project is to secure a suitable vessel arrangement. Nautilus aims to have this completed by the end of this year."

Sep 1, 2014

By W. G. Pariseau

This contribution describes rock mechanics features of the Davis Cavern at the former Homestake Mine in Lead, South Dakota, U.S.A. The mine is located in the northern Black Hills of South Dakota. In 2003 and again in 2008, the mine site was recommended for development as a national Deep Underground Science and Engineering Laboratory (DUSEL) in cooperation with the Sanford Underground Science and Engineering Laboratory under the South Dakota Science and Technology Authority (SDSTA). The original Davis Cavern was excavated about 9.1x16.8x9.7 m high (30x55x32 ft high) in 1965 (Mitchell 2009) at a depth of 1,478 m (4850 ft). The purpose of the cavern was to house apparatus for detecting solar neutrinos. The experiment ultimately proved successful and earned R. Davis a share of the 2002 Nobel Prize in physics. Recently, a new experiment (LUX=Large Underground Xenon detector for dark matter particles and WIMP's=weakly interacting massive particles) was proposed for the Davis Cavern that required an increase in height of 2.4 m (8 ft). For many years, the Homestake gold mine was the deepest operating mine in North America. Development extended to the 8000 Level (2,438 m). The mine closed in 2003. Pumps were shut off and the water level rose to the 4350 Level, about 150 m (500 ft) above the Davis Cavern. Some six years later after selection for DUSEL proposal development by the National Science Foundation (NSF), access to the 4850 Level and the Davis Cavern was regained. Pumping has lowered the water level to well below the cavern floor. Figure 1 shows the layout and location of the Davis Cavern (Cavity). Detector tank, supporting steel, and so forth were subsequently removed. The cavern was re-supported and new access was developed. By August, 2010, 13,000 ft3 had been removed during enlargement and renovation of the Davis Cavern. Figure 2 shows the detector tank under construction in 1965.

Jan 1, 2012

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The conventional rare earth element (REE) industry has historically sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive REE concentrations. These deposits are extremely uncommon, particularly in the USA. Given the criticality of these materials and the need for sustainable domestic supply, the current research seeks to leverage other autogenous processes that lead to concentrated REE resources. One such process is the generation of acid mine drainage (AMD). AMD is very common in many coal mining districts and results from the exposure and oxidation of pyrite during mining. During the generation and migration of AMD, liberated sulfuric acid mobilizes several metal ions including REEs. Treatment of AMD is required under U.S.C §1251, the Clean Water Act, and often consists of neutralization, oxidation, and metal hydroxide precipitation. To investigate the deportment of REEs during this process, a field sampling campaign was undertaken, whereby the concentration of REEs in AMD and AMD precipitates was measured directly. In the nine sites evaluated in this study, the REE concentrations of the precipitates varied from 29 to 1286 ppm with an average of 517 ppm among the sampled sites. The individual elements were enriched compared with the associated bulk Northern Appalachian (NAPP) coal material by factors ranging from 3 to 15. Furthermore, the distribution of REEs in all precipitate samples favored the heavy REEs (HREEs) when compared with traditional REE ores. This research represents the first part of multi-part research endeavor to characterize, classify, and determine the practicality of refining REEs from AMD and its by-products.

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The conventional rare earth element (REE) industry has historically sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive REE concentrations. These deposits are extremely uncommon, particularly in the USA. Given the criticality of these materials and the need for sustainable domestic supply, the current research seeks to leverage other autogenous processes that lead to concentrated REE resources. One such process is the generation of acid mine drainage (AMD). AMD is very common in many coal mining districts and results from the exposure and oxidation of pyrite during mining. During the generation and migration of AMD, liberated sulfuric acid mobilizes several metal ions including REEs. Treatment of AMD is required under U.S.C §1251, the Clean Water Act, and often consists of neutralization, oxidation, and metal hydroxide precipitation. To investigate the deportment of REEs during this process, a field sampling campaign was undertaken, whereby the concentration of REEs in AMD and AMD precipitates was measured directly. In the nine sites evaluated in this study, the REE concentrations of the precipitates varied from 29 to 1286 ppm with an average of 517 ppm among the sampled sites. The individual elements were enriched compared with the associated bulk Northern Appalachian (NAPP) coal material by factors ranging from 3 to 15. Furthermore, the distribution of REEs in all precipitate samples favored the heavy REEs (HREEs) when compared with traditional REE ores. This research represents the first part of multi-part research endeavor to characterize, classify, and determine the practicality of refining REEs from AMD and its by-products.

By Hyung Jeek Kim, Jongmin Joo, Jonguk Kim, Jai-Woon Moon, Kyeong-Yong Lee

"Co-rich ferromanganese crusts (Fe-Mn crusts) distributed on seamounts in the western Pacific are potential economic resources for cobalt, nickel, platinum, and other rare metals in the future. Evaluation and selection of a mining site can be established based on abundance and grade of Fe-Mn crusts in the site as well as topography that should be smooth enough for mining operations. Therefore, acquisition of shipboard echo-sounding and acoustic backscatter data are prerequisite to the selection of potential mine sites in addition to visual and sampling operations. Acoustic backscatter data can be used to locate crust-covered areas on a regional scale with the understanding of acoustic properties of crust through its correlation with visual and sampling data.During an expedition that took place from January to March 2014, KIOST collected geophysical and geologic data to assess the resource potential for Fe-Mn crusts on three seamounts (guyots) in the Western Pacific. In OSM11, one of the three surveyed seamounts, three camera tows were performed to observe the distribution of Fe-Mn crusts on the summit and slopes of the seamount. Although sediments of various thicknesses generally cover most of summit region of OSM11, several regions with high backscatter signals occur on the periphery of the summit. The occurrence of Fe-Mn crusts, observed during the camera tows, on those high backscattered regions suggests that the backscatter signals of shipboard multi-beam sonar can reflect changes in the geology of the seafloor from sediment layer to Fe-Mn crust deposits. The Fe-Mn crust deposited around the summit region is worthy of notice because of its topographic characteristics, including shallow depth, flat or gentle inclined surface, and smooth relief, which are more suitable for mining operation compared to the flanks of seamount."

Sep 1, 2014

By Antonio Raschillà

On the 2nd of June 2007 SELI S.p.A. started the excavation of Beles Tailrace Tunnel (Ethiopia). The new 8,07 m diameter DS Universal TBM utilized for the tunnel excavation was manufactured by SELI S.p.A. and allowed the installation of 30 cm thick concrete lining, contemporaneously with the excavation of 7,200 m of tunnel. The greatest part of the tunnel alignment was excavated in hard and sound basal-tic rocks. The paper describes the main steps of the tunnelling operations which led to a remarkably rapid excavation, with a peak production of 36 m / day and a final break-through achieved 46 days ahead of the contractual deadline. Furthermore the paper describes the work and logistic organization that was set up to efficiently perform the mechanized excavation in the very remote area of the project.

By Y. Q. Zhang, Y. Luo, S. S. Peng, C. T. Holland

Barrier pillars in underground coal mines could eventually be subjected to a hydraulic pressure head due to the build-up of mine water in the old workings. The pressure head could not only act as a force to destabilize the pillar but also cause seepage flow through the pillar and its surrounding strata. Excessive seepage flow could induce piping failure that in turn could accelerate the mechanical failure process of the barrier pillars. In this paper, finite element simulation approach has been employed in the evaluation of the barrier pillars. Both the stress distribution and the seepage flow pattern in and around a barrier pillar have been simulated numerically. The effects of ground stress on rock permeability to water seepage has been taken into consideration in these simulations.

Jan 1, 2001

By Rodger C. Fry

Underground coal mining has been active within the East Mountain property since the mid 1950's. As a result, coal from two seams has been extracted within large areas allowing surface subsidence to occur. Monitoring of subsidence annually, began in 1981 using on the ground conventional monumentation, surveying and photogrammetric monitoring. The data collected has shown the time benefits of photogrammetry and the relationship between observed subsidence and the geometry of the mined out area below.

Jan 1, 1986

By J. A. Botín

In modern mining, the core of mine planning and design is the block model, a simplified representation wherein the ore deposit is divided in a number of virtual rock cubes, each characterized by technical and economics parameters. Mining engineers use this model to design the mine and develop production schedules. Traditionally, sustainability issues are not considered in the mine design, planning and engineering processes but rather are incorporated in the later stages of the feasibility evaluation as necessary expenditures and operating costs. This paper describes the results of a research project aiming to develop a methodology to incorporate sustainability parameters directly into the block model, so that they become an integral part of the design, planning and scheduling processes. It is considered that the incorporation of sustainable parameters into the block model would yield a more responsible mine design and improve mining projects sustainability performance

Feb 27, 2013

By J. Donovan Jacobs

Many improvements in the art of underground excavation have appeared during the past two decades. These improvements have been both in methods and in machinery and have resulted in more economical construction of today's tunnels. In the realm of machines, the developments of continuous boring heads for either soft ground or rock, random arm excavators and the sliding tunnel floor (Magic Carpet) have each made contributions toward more rapid tunneling. CONTINUITY OF ADVANCE Tunnel boring machines are often referred to as "continuous excavators". Continuous advance (without cyclical interruptions) has not been achieved, however, in any of the machines now in use. In most rotary-head tunnelers the thrust needed to make the cutters bite into the face is obtained from hydraulic cylinders reacting against anchoring devices held stationary by pads which grip against the sides of the tunnel. With this system the forward motion of the cutting head is continuous only until the propelling cylinders have reached their limit of extension. At this point the grippers must be released, moved forward and reset before a new cycle of advance can be begun. Some machines are built to obtain their propelling thrust from hydraulic cylinders pushing backward against newly-installed rings of tunnel support. This is the customary method for propulsion of shields. With it, each cyclical advance or "shove" must await the erection of a new ring of supports. Faster tunnel driving

Jan 1, 1974

By D. R. Wilburn

The worldwide budget for non fuel mineral exploration was expected to increase by 27 percent in 2003 from the 2002 budget, according to the Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes after five years of declining spending for mineral exploration. For the first time in several years, all regional exploration budget estimates for 2003 as defined by MEG would increase from similar 2002 estimates. However, MEG included 193 more companies in its 2003 survey than in 2002. As with previous MEG survey reports, estimates reflect anticipated expenditures rather than actual dollars spent. Caution, therefore, must be taken when comparing 2002 and2003 estimates or evaluating the magnitude of regional changes from year to year. Sample variations and currency exchange rates may influence year-to-year variations of MEG data. Even so, it is likely that the general climate of improved metal prices in 2003 encouraged companies that had previously left the mineral exploration sector or reduced their exploration activity to once again focus on minerals exploration or increase exploration activity and budgets.

Jan 1, 2004

By Christopher J. Bise

INTRODUCTION Before a mine is planned in detail, a preliminary analysis is often conducted. This preplanning permits the mining engineer to make a rapid assessment as to whether or not a particular mining property warrants further consideration. In fact, a properly conducted preplanning phase can come within 10% to 20% of the actual results, thereby saving the mining engineer valuable time before committing himself to a fine-tuned analysis. The questions to be answered by mine preplanning are (1) What will be the operating conditions for the mine? and (2) How long will it take to complete the project? To answer these questions, calculations dealing with reserve estimation, production planning, man- power planning, and project scheduling are conducted. The following sections discuss these various phases of mine preplanning in greater detail. RESERVE ESTIMATION The estimation of the various characteristics of a reserve, such as quantity, grade, and thickness, is an ongoing process throughout the life of a mining venture. However, the reserve-estimation phase of mine planning is more closely associated with the preplanning phase. There are many different techniques employed in reserve estimation of solid mineral deposits; variations among them are introduced because of such considerations as ease of application or level of accuracy. In any event, each technique is developed in the following manner: (1) the mineral body is represented pictorially and then subdivided into blocks related to one or more samples of exploration data, (2) the area and volume of each block is determined, (3) the volumes are converted to representative tonnages (or, for example, grades), and (4) the results are tabulated. To illustrate this procedure, the polygonal (area-of- influence) technique will be presented due to its ease of application, flexibility in dealing with different deposits, and general acceptance. The polygonal method assumes that all characteristics of a mineral body extend halfway between a point of observation and any other point of observation. The explored portion of the mineral body is represented by polygonal prisms whose depths relate to the characteristic in question (grade, thickness, etc.) and whose plane bases relate to the area of influence of each point of observation (drill hole, etc.) as shown in Fig. 1. The polygons must be constructed in a definite order, usually clockwise and from the periphery to the center of the deposit. Table 1 can then be used to calculate the characteristics in question. Since, by definition, the polygonal method assumes that the characteristics of a mineral body extend half- way between points of observation, it becomes readily apparent that the evaluation of a vertical-drill hole exploration program requires that the sides of the polygons be formed by the intersection of perpendicular bisectors (Fig. 2). Figs. 3 and 4 show correct and incorrect construction of the polygons. The criterion for correct construction of the polygons is that all points within a particular polygon must be closer to its rallying point than those located in any other polygon. This is clearly not the case for certain points that are located in the polygon containing rallying point B in Fig. 4. Although this method can be used where the drill holes are irregularly spaced, calculations become less tedious when a square net (Fig. 5) or a chessboard (Fig. 6) grid is adopted. The numbers shown in Figs. 5 and 6 represent the relative weight for each of the shaded areas. In general, the greater the number of polygons, the more continuous the mineral body, and the more regular the grid, then the more accurate the computations will be. PRODUCTION PLANNING Before an acceptable evaluation of the production potential of a mine can be determined, a thorough exploration program should be conducted. It seems obvious that the nature and properties of the deposit and adjacent strata, the presence of impurities, and other mining conditions should be adequately determined prior to production planning and equipment selection. The lack of sufficiently detailed knowledge of the many mining parameters has led to the failure of numerous operations. For example, targeted production tonnages and equipment sizes for a coal mine are intimately related to the seam thickness. Needless to say the quality of information that is gathered from an exploration program can have a tremendous impact on the production plan. Production plans are developed initially by determining reasonable shift tonnages per operating section. Most of the time these values are developed from his-

Jan 1, 1986

By MAHESH SHRIWAS, CHRISTOPHER PRITCHARD

Ventilation monitoring and control in mines are becoming an integral part of day-to-day activity for maintaining the health and safety of miners. This paper evaluates potential real-time monitoring solutions for detecting and reducing diesel particulate matter (DPM), mine fires and dust in situ and examines the state-of-the-art use of ventilation monitoring and control in underground mines for detecting and reducing air contaminants to acceptable regulatory limits. In this study, relevant documents, including research papers, trade publications and manufacturer website information, are reviewed to identify research gaps. This paper also includes evaluations of contemporary sensors (airflow, gas, dust and silica), control system and software technologies, data transport systems, the Industrial Internet of Things (IIoT), ventilation network simulators and control devices to identify potential health and safety research gaps. Examples of some mines in Canada, Australia and the United States that have been using ventilation monitoring and controls are included as well. Overall, this review identifies multiple challenges and research gaps in applying mine monitoring and control systems that could be the focus of future research, offering potential improvements to miner safety and health and financial benefits.

By Paul Sarnoff

The economics of precious metals -- depending upon who is involved --could be the economics of hope, of fear, indeed of profit and perhaps survival. For those investors seeking capital gains in a puzzling economy, precious metals involve the economics of hope. Those who are convinced that currency soon won't be worth the paper it's printed on turn to precious metals because of the economics of fear. Gold and silver have been a storehouse of wealth since biblical times. The economics of fear during the past 500 years on the Continent has caused almost every European family to make sure a private stockpile or hoard of gold, silver or coins is at hand in case the paper currency of their country undergoes the kind of disaster that came to the German Mark after World War I. Understandably, for mining companies involved in the production of precious metals, the elements of operations and management are directly concerned with the economics of profit -- and perhaps survival. To the American miner the price of precious metals in the marketplace is a matter of daily concern. After decades of selling silver to the US Government at 64.64 cents an ounce, producing silver mines suddenly became faced with prices breaking $5, $10 and $20 per ounce, and approaching $50 an ounce during the period 1978-1981. What should the miner expect one year in the future? Five years?

Jan 1, 1981

By Kadri Dagdelen

Design of the ultimate pit limit to direct long range mine planning has been a celebrated problem in the mining industry, and in mining academia, since 1965. Although many papers have been presented on this topic, even today, there is not a single solution technique which is widely accepted and considered universally best. Many philosophical differences exist among the pit planners concerning the use of different methods and it appears that resistance is very strong towards accepting other techniques if you are a believer in one. Whatever the case might be, the pit parameterization technique for the ultimate pit limit design is the latest and takes a different approach than its predecessors. There are already a number of papers which discuss the concepts involved (Francois-Bongarcon, 1976; 1978; 1980; 1981); however, the aim of this paper is to fill in some of the gaps which are thought to be missing in the previous discussions and, in addition, to present the recent research done on the subject at the Centre de Geostatistique de l?Ecole de Mines de Paris in Fontainbleau, France. This paper is divided into two parts. The first part will discuss practical aspects and interpretations of pit parameterization concepts with- out using mathematical or theoretical arguments; the reader who is interested in the theory should refer to Francois-Bongarcon (1978). The second part will present an approach to obtain a complete double parameterization of reserves using an inexpensive (computer costs) single parameterization algorithm. A case study of this approach is also included.

Jan 1, 1982

By Sohta Takatsu, Hachiroh Mizubata, Shigeki Kudoh, Kazuya Takekuni, Yoshinori Yamada

A special type of shotcrete is used to improve the performance of open-type TBM in difficult situations. The Hakamagoshi and Johana tunnels are expressway evacuation tunnels of 3.2 km and 5.1 km in length, respectively (total 9.1 km) that were excavated by one open-type TBM. The geological conditions at the sites were estimated to be good before excavation. However, 95% of the rock turned out to be two ranking orders worse than the estimated classes. Therefore, we used a special shotcrete for bad rock conditions, and succeeded in excavating the tunnel at an average rate of 270 m/month.

Jan 1, 2001

By Laura McNally

In 2006 McNally International Inc. in a Joint Venture partnership with Aecon Constructors was the successful bidder on two York Region Tunnel Projects: Bathurst Collector/Langstaff Trunk Sewers; and YDSS Interceptor Sewer 19th Avenue Project. These projects comprise a total of 13 kilometres of 2.74 meter finished diameter tunnels and are both part of the York Durham Sewer System (YDSS). Both contracts require the use of EPB tunnel boring machines with a precast concrete segmental liner. The following provides an overview the two projects.

Jan 1, 2008

By İbrahim Çınar, Hakan Özşen

Mine workers in heavy and dangerous work are under several physical risk factors, for example temperature, humidity, noise, vibration, lighting and air velocity. Thermal comfort includes parameters such as air temperature, air humidity, air flow rate, radiant heat, metabolic rate and garment insulation. In this study, thermal comfort conditions were evaluated using thermal comfort indices defined as predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) which were determined by measurements taken from an underground coal mine for approximately 100 days. Although the metabolic rate (light work) was kept at 2 met, it was found that predicted mean vote ranged between − 2.58 and 1.68. The predicted percentage dissatisfied index was found to reach 95%. According to the results, it can be seen that thermal comfort may have negative effects on occupational health and safety. The change in thermal comfort index values in the Soma Underground Coal Mine was investigated in detail and the reasons for the changes were determined. Furthermore, determining the optimal working environment for the mine workers was also an aim of this study.

By J. W. Davis

In the last few years major industrial companies have begun to realize the importance of Reliability as an enterprise strategy that, properly implemented, will improve financial performance. Typical results of an effective Enterprise Reliability Strategy include a 20% -50% reduction in maintenance cost accompanied by a 5% - 10%increase in real production capacity, with no capital investment in production equipment. One factor fueling the race to acquire and implement enterprise reliability is the pressure for companies to be increasingly cost-effective and competitive in global markets. In a recent study, Asset Productivity: The Next Wave, the Boston Consulting Group (BCG)stated that, “In order to compete for funds, companies must offer investor returns that are competitive with other opportunities. Alternative investments such as dot-com and others with non-traditional business models have raised the bar.” (APDF version of the study can be downloaded at www.bcg.com). BCG views asset productivity as the most powerful mechanism for increasing shareholder return. The author believes that the most effective way to increase Fixed Asset Productivity is to maximize asset utilization by increasing the Reliability of the Assets and the associated processes. Developing and implementing an ERS requires significant effort and knowledge. Most companies have difficulty finding a sufficient supply of these valuable commodities to implement an ERS Program internally. Many companies also struggle with figuring out how to get started and what direction to proceed.

Jan 1, 2003

By Zhenqi Cai

The ongoing Overpeck Valley Parallel Sewer Project of Bergen County Utilities Authority (BCUA), New Jersey, is a US $65 million CSO improvement program to meet a State DEP consent order by 2010. One major program component includes a total of 1.8 km (1.2 mile) long, 1,800 mm (72 in) diameter reinforced concrete pipe (RCP) installed by a Herrenknecht AVND1800AB MTBM. The alignment includes drives through 850 m (2,788 ft) of extremely soft glaciolacustrine varved clay, 980 m (3,214 ft) of loose to medium dense mixed soils containing silty sands, gravels, and boulders, and crosses under the New Jersey Turnpike, US Highway Route 46, and a CSX Railroad Intermodal Yard and a branch mainline. Two types of MTBM cutterheads are being used, one configured for the weak varved clay, and one for the mixed soil conditions. The MTBM is also equipped with a double-steering system consisting of a standard front steering joint and a second trailing steering joint to assist grade control should adequate steering not be achieved by the front primary steering in extremely weak soil conditions. This paper discusses the significant engineering aspects and challenges related to site settings, ground characterization, key MTBM features and performance, and required ground treatment.